According to the Environmental Protection Agency (EPA), air sparging is the most developed innovative in-situ technology for groundwater remediation in USA. Air sparging systems are easy to implement, and relatively simple to operate. In addition, it is a relatively low cost remediation technology that can be applied in conjunction with other remediation technologies. For these reasons, air sparging has become widely used. In this book the investigation of various “rule of thumb” design protocols for air sparging using a cross-flow two-compartment numerical model to improve the efficiency of air sparging. A numerical model was developed by the author and presented here was concurrently used with multiphase flow software. The recent developed model considers the contaminant concentrations in the two compartments: gas and dissolved phases. Mass balance has been applied for deriving a pair of linked partial differential equations. A numerical technique solution using the finite difference method has been used simultaneously in solving for the contaminant concentration in both gas and liquid phases. An analytical solution has been derived and verified with the numerical solution.